This invention relates to a roll control actuator for a roll control system of a motor vehicle.
It is known to provide a roll control system for a motor vehicle which comprises a torsion bar which is formed in two parts, with an actuator positioned between the two parts. The actuator is controllably actuated to either allow free relative rotational movement of the two parts of the torsion bar about their longitudinal axes (for example, during straight line motion of the motor vehicle), or to create a torque between (or lock) the two parts together (for example, during cornering of the motor vehicle). Known roll control actuators, as, for example, described in GB-A-2212770 and GB-A-2220625, are complicated.
It is an object of the present invention to provide a roll control actuator which overcomes the above mentioned disadvantage.
A roll control actuator in accordance with the present invention for installation between first and second axially aligned parts of a torsion bar comprises a cylindrical housing connectable by an end wall to the second part of the torsion bar; a rod positioned inside the housing, extending out of the other end of the housing, and connectable to the second part of the torsion bar; a cylindrical inner sleeve positioned inside the housing between the housing and the rod; the housing, the rod, and the inner sleeve being coaxial on an axis, the rod being rotatable about the axis relative to the housing; securing means for securing the rod and the housing together to substantially prevent relative axial movement; first linking means between the housing and the inner sleeve, the first linking means generating rotational movement of the housing about the axis on axial movement of the inner sleeve; second linking means between the inner sleeve and the rod, the second linking means generating rotational movement of the rod about the axis on rotation of the sleeve about the axis, and allowing axial movement of the inner sleeve relative to the rod; and control means associated with the inner sleeve to control the relative rotational movement between the rod and the housing.
The roll control actuator in accordance with the present invention is much simpler, and hence easier to assembly, then previously known actuators.